I was booting a new VMWare Virtual Machine with Windows PE through Altiris for initial deployment but Windows PE halted with a BSOD:

0x0000005D means UNSUPPORTED_PROCESSOR (defined in bugcodes.h) so I expected there was a x86 vs x64 problem.

The VM was configured for a 32 bit OS:

The Altiris Job was configured to use Auto Select:

But instead of the x86 version of Windows PE, Altiris attempts to boot the x64 version and this explains the BSOD: VMWare prevents the CPU from going to x64 mode and thus Windows has no choice but to halt.

Workaround is to change the Automation pre-boot environment in Altiris to x86:

Note that it’s no problem to deploy an x64 OS using the x86 version of Windows PE so I don’t see any real problems with this workaround.